Coding mechanism



y 1940- E. s. LARSON 2,207,744

comm MECHANISM Original File d Dec. .31, 1935 2 Sheets-Sheet 1 b2 b w m. 22

2} 4 o8 i senie; LQhQJ 207 9 I g 20s 3? h 201 5 INVENTOR. EDWARD S. LARSON Arr RNEY. 1

July 16, 1940, E. s. LARSON 2,207,744

' comm MECHANISM Original Filed Dec. 31, 19:55 2 Sheets-Sheet 2 INVENTOR. EDWARD S. LARSON ugpam ATTORNEY.

. [2,207,744 PATEN OFFICE.

CODING MECHANISM Edward-S. Larson, Chicago, Ill., assignor to Teletype Corporation, Chicago, 111., a corporation of Delaware Original application December 31, 1935, Serial No. 56,924. Divided and this application April 3, 1937, Serial No. 134,871

Claims.

This invention relates totranslating devices, and particularly to a mechanism for controlling combinations of electrical impulses for transmission telegraphically.

5 This application is a division of application Serial No. 56,924, filed December 31, 1935, by E. S. Larson and C. A. Levin. I

An object of the invention is to set up codes for combinations of characters and insure proper transition from one character combination to another.

A further objectof the invention is to provide easily fabricated unitary conductive members for,

supplying the combinations of electrical impulses. 15 The invention features a code and corresponding conductive commutator surface in which the number of elements representing like impulses of any code combination differs from the number of such impulses in the immediately preceding or 20 succeeding code combination by one impulse plus or minus. v

In one embodiment of the invention, there is provided a pair of commutators, against each of which a set of conductive brushes is pressed.

' Each of the commutators comprises a drum or cylinder to the surface-of which a metallic sheet having portions cut away in accordance with any desired code is secured. The commutators are geared together for rotation at predetermined ra- 30 ties, as ten to one, when figures are to be transmitted. The commutator cylinders are driven by a motor controlled in accordance with the character to be transmitted. One brush of each set engages a continuous conductive surface 5 around the commutator drum and applies a transmitting potential thereto. The remaining brushes serve as collectors and deliver impulses to a distributor. The brushes associated with the slow moving drum are mounted on a yoke 40 which serves as an armature for an electromagnet. The electromagnet is controlled from one .of the brushes engaging the fast moving drum and operates the yoke to shift the brushes mounted on the yoke circumferentially of the 5 drum. This arrangement is particularly adapted,

to the transmission of figures, in that it insures a change of digit in the secondary position asthe primary digit changes. in either direction be tween nine and cipher.

The translating or coding mechanism which embodies the invention will be shown and described'as part of asystem for automatically transmitting meter readings representing the condition of a plurality of electrical circuits in rapid succession. It is not to be concluded from this that apparatus in accordance with the invent-ion is limited to use in the transmitting system shown, as the meter indication transmitting system afl'ords' merely one convenient use of the 60 translating device.

For a thorough understanding of the inven-..

tion, reference may be had to the following detailed description taken in connection with the accompanying drawings in which;

Fig. 1 is a schematic circuit diagram of a meter reading transmission system in accordance with the invention;

Fig. 2 is a plan view of one embodiment of a translating unit;

Fig. 3 is a sectional elevation taken on the line 33 of Fig. 2;

Fig. 4 is a schematic representation of a portion of a registering meter;

Fig. 5 is a chart of a set of code combinations which may be employed, and Y Fig. 6 is a plan view of a conductive plate which may be applied to a translating unit commutator cylinder.

Referring now to the drawings, in which like reference characters designate corresponding parts' throughout the several views, and particularly to Fig. 1, the reference numeral l l designates a meter for giving an indication of the condition of an electrical circuit, such as a voltmeter, and the numeral l2 designates a meterfor giving an indication of .a difierent'condition, such as a wattmeter. The voltmeter II has one terminal connected by a conductor I3 to the fixed contacts of a plurality of switching relays iBa, "SD, 169, and in. The movable contacts or armatures of the relays 16a, I61), 18g, and i671. are connected respectively to one terminal of the secondary windings of the transformers Ha, l'lb, Hg, and llh. The other terminal of the meter II and of the secondary windings of each of the transformers l'la, "b, Fig, and ilh is grounded, and

the primaries of the transformers are connected to any. power lines the voltages of which it is desired to read. Upon energization of any of the switching relays Ilia, 16b, llig or I611. the -.voltrneter II will be connected to the corresponding power .line transformer and the voltmeter pointer will be deflected to indicate the voltage condition within the selected power circuit.

The wattmeter I2 is connected by a conductor 18 to one contact of a normally open contact pair, associated with each of the switching relays 2la, Zlb, 2lg, and 2th and the other contact of each of the pairs is connected to one terminal of the secondary windings of the transformers 22a; 22b, 22g, and 22h respectively, which may be voltage transformers for impressing upon the wattmeter l2 a voltage condition. A conductor l9 connects the wattmeter I! to one contact of another normally open contactpair associated with each of the switching relays 2la, Zlb, Zig, and 2.lh, and the other contact of each of last mentioned pairs is connected to one terminal of thesecondary windings 'of the transformers 23a; 231:, 23g, and 23h respectively, which v will be connected to the wattmeter to cause a deflection of the meter pointer in accordance with the power condition in the selected power circuit.

The meters II and I2 may be recording meters of any well known commercial type, having an element movable with the meter pointer to give an indication of the position of the pointer. One possible arrangement is shown schematically in Fig. 4, the electrical circuits therefor being shown in Fig. 1. The meter is provided with an indicating pointer 29. At opposite sides of the pointer are contact arms 21 and 29 mounted on non-conductive segment 26 and provided with.

contacts 29 and 39 respectively The non-conductive segment is carried by a shaft 3I which is mounted coaxially with the pointer 29 and which may rotate through an arc equal to the range of movement of the pointer The shaft 3| may be provided with gear 32 meshing with warm 33 carried by shaft 44 which is driven from motor 35.

As shown in'Fig. 1, battery is applied to the pointer 29 of the meter II from contact arm 39 of gang switching relay 31 when the relay is energized and to the pointer 29 of meter I2 whenrelay 31 is deenergized. A switching relay 39 is connected to the contact 29 of each of the meters, and a switching relay 39 is connected to the contact 39 of each of the meters. Each of the relays 39 and 39 is operable to clos'ethree pairs of contacts upon engagement of a meter pointer 23 with a contact 29 or 39, if battery is then applied to that pointer through the contact arm 39 of relay 31. Upon closure of the three contact pairs associated with a relay 39, battery is applied through the outermost contact 'pair I25 to the field of motor 35, the return from the field being through the intermediate contact pair I29 to ground. The innermost contact pair I21 completes the circuit of the armature of motor 33 to cause the motor to drive the shaft 34 and through it the member 3|, and thus to move the contact arms 21 and 29. It will be understood 4 that engagement between a pointer 29 and contact 29 will be due to deflection of the pointer by reason of the application of a potential difference across the meter. Battery is applied to the field of motor 35 in that electrical sense whichwill drive the motor in a direction to cause the contact arm= to recede' from the advancing pointer. The contact arms 21 and '29 thus travel with the pointer 26 until the pointer comes to rest, whereupon further movement of the contact arms results in disengagement of the contact 29 from the pointer 26 and removal of battery from relay 39. The release of relay 33 permits the three associated contact pairs to open, and motor 35 comes to rest.

When the movement of pointer 26 is in a direction to bring it into engagement with contact 39, relay 39 is energized and its associated three contact. pairs are closed. The closure of the contact pairs completes the circuits of held and armature of motor 35 as in the case of the operation of relay'39, except that battery is applied to the field inthe opposite direction, and motor 3| is driven in opposite direction, to cause contact arm 29 to recede from pointer 29.

As shown in detail in Fig. 2, and schematically in Fig. 1, there is provided a translating unit for interpreting a meter pointer position and coding the meter reading permutablyin impulses capable of transmission telegraphically. The translating unit comprises a base H which supports the motor 35 and on which are mounted shaft supporting blocks 42-42 and 43-43. Blocks 42 support rotatable shaft and blocks 43 support shaft 34. Shaft 44 carries a pinion 48 secured thereto and meshing with worm 41 carried by the armature shaft of motor 35. Shaft 44 also has secured thereto gear 49 which drives gear 5| which is secured to shaft 34. The ratio between gear SI and gear 49 is 10 to 1, so that shaft 34 revolves once for ten revolutions of shaft 44.

The motor driven shafts 34' and 44 support commutator's 52 and 93 respectively which are identical, for which reason the description will be confined to one commutator.

In one embodiment the commutator consists of a non-conductive cylinder 54 mounted on the shaft 34 or 44 and having arranged upon the periphery and in conformance with the surface thereof a conductive plate 59 which in certain areas entirely surrounds the cylinder. The plate 55 which may be secured to the cylinder 94 by any desired means has apertures 59 therein through which portions of the surface of the non-conductive cylinder are A plan view of one of the plates 55 before being curved to conform to a cylinder 94 is shown in Fig. 6. The plate 59 is of predetermined, irregular contour by virtue of the fact that portions are cut away. Although the plate 59 is a unitary structure, its surface affords a plurality of zonal areas, Preferably flve in number, each zonal area extending from end to end of the plate and aflording peripheral zones when the plate is applied to one of the commutator cylinders 54. The zones are indicated in Fig. 6 by the reference numerals I, II, III, IV V.. The zone desig nated V is metallic without interruption, whereas each of the other zones has cutaway portions 59. The'surface of the plate 55 also comprises zones extending transversely thereof and designated by the numerals 0 to 9 inclusive in F18. 6. Each of the zones 0 to 9 differs from every other zone in the relative positions of metallic surface and cutaway portion. Thus zone 0 is metallic where it concides with zones III, IV, and V; zone 1 is metallic where it coincides with zones I, III, IV. and V; zone 2 is metallic where it coincides with zones 1, III, and V, etc.

. Attention is now directed to Fig. 5, which indicates in tabular form a code for coding numbers. The first column contains the numbers from zero to nine. Opposite each number is an indication of the relative arrangements of code impulses on the basis of a four unit code, which isample for coding the ten primary numbers;

pulses will be assumed to indicate current on the line, and spacing lmpulseswill indicate a no-current condition. In the table of Fig. 5 blank rectangles may be assumed to indicate spacing impulses and numbered rectangles may be assumed to indicate marking impulses. Thus zero is represented by marking impulses in the third and fourth impulse positions, the digit 1 is represented by marking impulses in the first, third, and fourth impulse positions, the digit 2 is represented by marking impulses in the first and third impulse positions, etc.

Now, drawing a comparison between the table of Fig. 5 and the contour of the plate 55 shown in Fig. 6, it will be observed that the first impulse in the code of each of the numbers 1 to 7 inclusive is marking, and that plate 55 is metallic where zones 1 to '7 inclusive coincide with zone I; that the second impulse of numbers 5 to 9 inclusive is marking, and that plate 55 is metallic where zones 5 to 9 inclusive coincide with zone II; that the third impulse of numbers 1, 6, '7, 8, and 9 is marking, and that zones 1, 2, 6. '7, 8, and 9' are metallic where they coincide with zone III; that the fourth impulse of the code of numbers 0, 1, 4, 5, 6, and 9 is marking, and that zones 0, 1, 4, 5, 6, and 9 are metallic where they coincide with zone IV. Similarly, those portions by which plate 55 fails to be a solid rectangular plate corresponds to the blank rectangles of Fig. 5. Zone V is not mentioned in the above comparison, for the reason that it 'bears no relation to the coded portion of the transmission, or due to slight variations in aligncommutator but serves as a means for supplyin potentials to the coded portion, as will be described later.

The code arrangement is shown in Fig. 5, and

embodied in conductive material in the plate in Fig. 6, has been developed with the aim of having definite relationships between the code combinations of the several digits. The relationship is that the code combination for any digit differs from that of its preceding or succeeding digit by one code impulse. Not only is the difference one impulse, but any two successive digits have at least one impulse of each in the same code position, successive digits coded in two and three impulses each have two impulses in the same code positions, and as between three-impulse and four-impulse codes, three impulses ofeach occupy the same code po- 'sitions. Thus zero has impulses 3 and 4; 1 dif- -fers from zero by the addition of impulse 1; 2

differs from 1 by thesubtraction of impulse 4; 3 differs from 2 by the subtraction of impulse 3; 4 differs from 3 by the addition of impulse 4; 5 differs from 4 by the addition of impulse 2: 6 differs from 5 by the addition of impulse 3; '1 difl'ers from 6 by the subtraction of impulse 4; 8 differs from '1 by the subtraction of impulse. 1: 9 differs from 8 by the addition of impulse 4; and zero differs from 9 by the subtraction of impulse 2. Thus the sequence of numbers of impulses for the digits zero to 9 inclusive, is two. three, two, one, two, three, four, three, two,'three.

With the arrangement described in the preceding paragraph, the possibility of error'in codin digits is minimized. When in the operation of the commutator a marginal condition is encountered, wherein, by an imperceptible movement of the commutator one way or the other either of two adjacent code combinations may control ment of the contactors which cooperate with the coded commutator, certain contactors may enuse an area representing one code combination and others may engage an area representing another code combination, no combination of impulses can be applied to the contactors which differs from the codes of both of the areas. Thus, one or the other of the two code combinations between which the contactors are attempting to differentiate will be applied to the transmitter, and these code combinations represent numerical values differing by the numeral value one (1). In the specific embodiment of the invention described herein, such a marginal condition of operation can occur only in the coding of units values, as a feature to be described later avoids such marginal conditions in the coding of tens values.

Adjacent to commutator 53 there is mounted on the base M a block 56 of non-conductive material. A plurality of brushes are mounted on the block 56, there being a brush 5! to cooperate with each of zones I, II, III, and IV and a brush 61' to cooperate with zone V. The brushes 58 which cooperate. with zones I, II, III, and IV and brush 68 which cooperates with zone V of commutator 52 are mounted on a strip 50 of nonconductive material carried'by a metallic yoke 64 which is pivotally mounted on the shaft 34. A fixed rod 62 (Figs. 2 and 3) disposed within an aperture 53 in an arm of the yoke 6| limits the distance through which the yoke 5| may move about the shaft 34. The yoke 6| is biased to its uppermost position by a spring 54 engaging an extended portion of an arm of the yoke. Mounted belowthat portion of the yoke which supports the non-conductive strip 50 is an electromagnet 56 for which the yoke 61 serves as armature.

The electromagnet 55 of the translating unit is operable, as is apparent from Fig. 3, to rotate the yoke 6| counterclockwise against the tension of spring 54', whereby the brushes 58 are shifted 40 from the full line to the. dotted line position of Fig. 3. Upon deenergization of the magnet, the spring 54 restores the yoke GI and brushes 55 to the unshifted position. v The purpose for which this shifting of brushes is provided is to insure a sharp line of division between adjacent signal combinations as applied to the brushes 58 by the commutator 52. Since the commutator 53 completes one revolution for each one-tenth revolution of the commutator 52, it is desirable that as in the opposite direction and passes from 0 to 9,

the commutator 52 shall present the code combination area corresponding to the next lower tens digit -to the brushes 58. The shifting of the 'brushes55 by the electromagnet 65 insures the proper carry-over as between the units and tens digits signals. X

The preferred control of the electromaget is from a circumferential portion of the units commutator 53 which changes in character between 9 and 0. It will be noted in Fig. 6 that zone 11 is conductive in the area corresponding to the digit 9 and is non-conductive in the area corre sponding to 0. The brush which engages that zone is the second of the brushes 51. This brush may be connected to one terminal of the winding of the magnet '55, which may have its other terminal grounded, so that when the brush engages the conductive portion of. the commutator,

th which a source of potential is connected, the magnet will be energized and the brushes will be shifted. The connections for the magnet 88 are shown'in Fig. 1.

As indicated in Fig. 6, by the change zone II from a conductive to a non-conductive condition between the digits 5 and 4, the magnet 88 will be energized as the commutator 88 passes from 4 to 5 and will be deenergized as he commutator passes from 5 to 4 so that th brushes 88 will be shifted. The rotational relationship between the commutators is such that the central portion of an area representing a tens digit will be presented to the'brushes 58 when the area of commutator 58 representing the digit 4 or the area representing the digit 5 is presented to the brushes 81, and the shift of the brushes 88 is not signal combination presented to the brushes 58.

The zones V with which the brushes 81 and 88 contact are uninterruptedly metallic, so that a continuous peripheral conductive strip is formed around the commutator with which the remaining metallic surface portion of the commutator is electrically continuous. Battery is permanently connected to the brushes i1 and 88, and thus the potentials are delivered to those'of the brushes 81 and 88 which, for any positions of the commutators I2 and 88, engage metallic portions of the surfaces thereof. The brushes 51 and 88 are I connected to other electrical-apparatus in the manner shown in Fig. 1.

As shown in Fig. 1, two of the translating units 4l-4i are included in the system, there being one associated with the voltmeter. and another associated with the wattmeter l8.

In Fig. l, the reference numeral 18 indicates a transmitting distributor which is employed for impressing on a telegraph line the permutation code impulses derived from the translating units. Transmitting distributor 18 comprises a continuous conductive ring 1|, a segmented ring comprising a plurality of conductive segments to which reference characters maybe applied as .ting distributor lllis connected to the telegraph line 11 over which signals are to be transmitted, and by means of the ring 1| cooperating with its brush, signaling impulses are impressed upon the telegraph line.

The transmitting distributor herein employed is intended for use in transmission by the startstop system in which each group of impulses representing a character or printer function is pre ceded by a start signal and is followed by a stop signal. The series of distributor segments hereinbefore mentioned supplies to its brush the start and stop signals as well as the character impulses. In Fig. l the segments of the distributor which furnish start and stop signals have been designated by the letter S and by reference nuerals'16 and 88 respectively, and the segments which transmit character code impulses have been numbered 1 to 5 in groups, as the particular distributor disclosed will accommodate a permutation code of five units, whereas a four unit one of segments 88.

code will accommodate the transmission of the meter readings.

The brushes ofthe translating units deliver signaling impulses to the segments of the transmitting distributor through fixed contacts and movable contact arms of two switching relays, one of which is designated by the reference character 81 andthe other by he reference character 18. Each of the relays 31 and 18 has ten movable contact arms. Each of the contact arms of relay 81 is movable between two contacts and the eight brushes of the translating unit asso gized; The eight brushes of translating unit v which is associated with wattmeter I! are connected to contacts of relay 81 that are engaged by the contact arms 18 when the relay is energized. The eight contact arms 18 of relay 81 which engage contacts connected to the translating unit brushes are connected to eight fixed contacts 8| of switching relay 18. The eight contact arms 82 which cooperate with the eight fixed contacts 8| of relay 18 are connectedto numberedsegments of the transmitting distributor, four being connected to the four segments designated 85 immediately following the first start segment and the remainder being connected to the four segments designated 88 following the second start segment. The conductive paths to the segments 85 and 88 of the distributor are continuous through the contact arms of relay 18 when the relay is deenergized and are interrupted at those points when the relay is energized.

In addition to the contact arms 88 and 18 hereinbefore described, the switching relay 81 has a movable contact arm 84 which is con- .nected by a conductor 88 to one end of the winding of a switching relay 81, the other end of which is connected by conductor 88 to one of a pair of cam operated contacts 88 associated with the transmitting distributor 18, the other contact of the pair being connected to grounded batteryi The contact arm 84 is movable be-- tween two contacts, each of which is connected to the indicator pointer of one of meters H and I2, the arrangement being such that when relay 31 is deenergized the pointer of meter II is con nected to conductor 88 and relay 81 and when relay 81 is energized the pointer of meter I8 .is connected thereto.

'arm 85 when the relay is energized. By means of contacts 9|, battery is applied to the fourth one of distributor segments 85 and to the second Through contact 88 and contact'arm 84 battery is applied to distributor segment 86 which is the third segment following the third start segment 18." Contact arm 88 engages contact when relay 18 is energized to establish a locking circuit for relay 18 by virtue of conductor 81, contact arm 88, and contact 88 of switching relay MI, and battery I88, it being understood that relay IOI must be energized in order for the locking circuitto be established.

Switching relay llll becomes energized upon having battery applied thereto through cam operated contact pair I08 associated with the transmitting disributor 18. The contact pairs 88, previously mentioned, and I03 are closed by cams I04 and I05 rotated by the shaft 69. The cams I04 and I05 are'so disposed on shaft 69 with respect to the brush arm 13 that both contact pairs are closed when the distributor brush leaves the fourth segment in group 83. Contact pair I03 opens immediately after the distributor brush passes from segment 96, but contact pair 39 remains closed until the distributor brush passes onto the first segment of group 85. The timing of opening and closing of the contactpairs 89 and I03 with respect to a cycle of operation of the brush arm I3 is clearly indicated by the lengths of the dwells of cams I04 and I05.

At the left of Fig.1 there is shown a sequence switch consisting of four banks of contactsdesignated- 20I, 30I, 50I, and GM over which sweep I contact brushes designated 202, 302, 502, and 602 are connected together and to relays in the 2!- respectively. The brushes are stepped around the contact banks by a stepping magnet I I I which is energized from battery I02 through contact pair II2 when relay IOI is energized. The first contact of each bank designated 203, 303, 503, and 603 is connected to the brush of that bank, and those contacts are connected together parallelly by the conductor I I 3 to which grounded battery H is connected, whereby all of the brushes are electrically connected to each other and to battery.

Referring now to contact bank 20I the second contact 204 is connected by conductor 206 to one side of the winding of switching relay I9, the other side of the winding being grounded. The third and fourth contacts designated 201 are connected together and to one side of the winding of relay 2 la, and similarly all succeeding pairs of contacts series, examples being contacts 200, 209, and 2I0 connected respectively to relays 2Ib, 21g, and 2Ih. Those connected contacts between contacts 208 and contacts 209 are intended for connection with other switching relays similar to relays 2Ia and 2Ib, and such other relays will connect to other power circuit transformers similar to 22a. and 23a.

Each of the relays 2Ia, 2), etc. has one end of its winding grounded.

Contact bank 30I'ha" its second and third contacts, designated as 304,con'nected together, its fourth and fifth contacts, designatedas 306, connected together and so on around the bank, leaving a single contact 309 at the end of the bank. Contacts 304, 306, 301 and 308 are connected respectively to the windings of switching relays 16a, lSb, I69, and I6h. The additional connected contacts shown may connect to additional relays similar to I6a which control additional power cir-, cuit transformers similar to Na. Contact 309 is connected by conductor 3I0 to contacts 304 and therefore to relay IISa.

It is important to note at this point that brushes 202 and 302 engage associated relay cir-.

cuits a period of time represent (1 by two contacts of the bank, by reason of .the e trical linking of the contacts in pairs. It is also to be noted that the comparative arrangements of connections to contact banks 20I and'30I are such that" brushes 202 vand 302 although they are stepped simultaneously apply battery to successive switching relays alternately, and therefore that meters II and I2'are transferred from one power circuit t another alternately.

Contact bank 50I has its second and third con- .tacts idle, and beginning with the fourth contact, designated 504, alternate contacts are connected together, and by conductor 506 to one side of the winding of switching relay 31, which has the other side of its winding grounded.

Contact bank GM has all of its contacts beginning with the third, which bears reference character 604, connected together and by conductor I I! to fixed contact I I4 of relay 81. Movable contact arm II5 of the relay engages contact II4 when the relay'is deenergized and is connected by conductor I20 to start magnet I5. The circuit.

of start magnet I5 is thus broken when contact arm H5 is attracted by relay 81, which occurs when cam operated contacts 09 are closed and contact arm 04, on relay 31, engages a contact associated with either of the pointers 26 of meters II or I2 and the pointer thus connected in the circuit engages either of its contacts 29 or 30. Battery may also be connected locally to start magnet '15 by closing key I 16. I

The meter reading transmitting system herein described is intended for transmission to a printing telegraph apparatus, particularly of the page printing species. For a complete understanding of a printing telegraph apparatus which may be employed for receiving the signals and printing. the meter readings, reference may be had to United States Patent 1,904,164 to Morton et al., April 18, 1933. In the embodiment of the invention herein described, local control of the transmitting apparatus is contemplated through the agency of the manually operated key I It. It is to be understood that remote control may be provided, to be effected from any desired point, such as the location of the receiving printer. Such remote control could be effected in the manner disclosed in 'Patent 2,057,083 granted October 13, 1936 to J. O.

other piece of apparatus. It is to be noted that all batteries have one side connected to ground and that all pieces of apparatus to be actuated by said batteries also have one side connected to ground, so that a common return for all battery circuits is provided.

Before proceeding with a description of the operation of the system for transmitting power meter readings, the idle condition of the apparatus when it is in condition to be started for a the transmission of signals will be described. Fig. '1 shows the apparatus in such idle condition, except for the fact that all relays have been shown unoperated, whereas certain ones of the relays are'energized in the idle condition preparatory to the transmission of signals. When the apparatus is idle, the brushes I2 of the transmitting distributor I0 are restrained from rotation by the latch I4 due to the fact that start magnet I5 is deenergized. In this position the contact pair 89 is closed and battery is applied to the switching relay 81 which will'be energized only if one of the meter indicator pointers 26 is in engagement with one of its contactsi29 or 30, whereby it is connected to ground through one of its associated switching relays 38 or 39. Under these circumstances the common return afforded by the the banks of -contacts. Through'sequence switch brush 202 and conductor fitt'battery is applied to switching relay i8 so that this relay is energized and the translating units are disconnected from the transmitting distributor, and instead battery is applied to the fourth of the distributor segments as and to the second oi the segments. 83. Through sequence switch brush 302 the switching relay its is energized by virtue of its connection to contacts 304 of sequence switch contact bank tilt, the first of which is engaged by the brush 302. The energization of the switching relay I631 causes the secondary of transformer I'la to be connected to meter Ii, thus maintaining its indicator pointer 26 deflected due to a potential difference across the transformer Ila. The deflection or the pointer 26 results in energization oi one or the other of the switching relays 38 and 39 so that the motor 35 is operated and the associated translating unit 4| is set for the coding of the reading of meter N. If the pointer 26 arrives at a steady deflection, relays 28 or 39 will be deenergized, the motor 35 will be stopped due to disengagement of pointer from contact 28 or 30 and disconnection of battery from switching relay 38 or 39, and the apparatus will be ready for the transmission of the reading of meter i I. Under this condition the switching relay 8? will be deenergized because it must be connected to ground through relay 38 or 39,'contact 28m 30, and pointer 26 in order to be energized, and the contact ill and H5 closed to permit energization oi the start magnet I5 by application of battery through the key I I6 when that becomes desirable. Should the pointer 26 not come to a steady deflection, the start magnet 15 cannot be energized for the reason that magnet 81 would be energized and contacts Ill and [I5 opened, thus preventing connection of the start magnet ii to battery. All of the other relays of the I8 series and all of the relays in the 2| serieswould be deenergized with the sequence switch set as shown, and the meter I2 and its associated switching relays and translating unit would be unoperated. The relays 21 and IOI and the stepping magnet III of the sequence switch would be deenergized.

Operation the brushes may traverse the several segments.

Upon passage of the brush over the first of the segments I6, the proper start pulse for starting the receiving printer is transmitted. As only the fourth of the segments is connected to battery under these circumstances, the proper code combination is transmitted to effect a carriage return j operation in the receiving printer and in this way its carriage may be returned to the beginning of a line. The brush then traverses the first stop segment 80 and the second start segment l8, which segments condition the receiving printer to receive the next code combination. As the next group of signal transmitting segments is traversed, battery is encountered atthe second of the segments 82 and the signal combination thereby transmitted constitutes a line feed signal whereby the page,

1 upon which the meter readings are to be printed is advanced to present a new line to the printing point. As the distributor brushes leave the last of the segments 83, the contact pairs 88 and I are closed. Through contacts I02 battery is applied to switching relay I III and the relay is energized to attract its armatures, thereby closing the contacts 98 and 99 and the contact pair H2. The contacts 98 and 99 complete a locking circuit for the switching relay I8 from battery I 22 through the conductor 91, contact arm 95, and

\ fixed contact 93. The closure of contact pair II2 permits the stepping magnet I I I to be energized to advance the several sequence switch brushes to the next position. 'Continued movement of the brushes of the transmitting distributor causes the transmission of stop and start signals, after which the third group of numbered segments is traversed. The only segment of this group which is at any time connected to battery is the segment 96 and in this phase of the operation of the apparatus, no potential is applied to segment OI by reason of the fact that contact arm 94 of'switching relay i8 is out of engagement with the fixed contact 92 due to the energization of the relay. After the brush has traversed segment II, the contact pair I03 opens, permitting relay III to be deenergized, the stepping magnet II'I becomes I deenergized and returns to its normal position,

and the locking circuit on relay 18 is removed. which causes it to become deenergized and causes the brushes of the translating unit II that is associated with meter I I to be connected to the segments of the transmitting distributor. The transmitting distributor brush completes its cycle by traversing the final stop segment and thus returns to the point of beginning. The contact pair 89 has remained closed during this period and if the indicator pointer 28 of voltmeter II has not remained steadily deflected, and as a result the pointer 26 has touched either of the contacts 29-. or 30, the relay 81 may be actuated to prevent the energization of start magnet II and release of brush arm I3 which would otherwise occur upon advance of the sequence switch brushes and the resultant engagement of brush "2 with contact 604.

Before describing the next cycle of operation of the transmitting distributor, the circuit changes produced by the stepping of the sequence switch brushes will be described. Brush 202 has ad- ,vanced to the first of contacts 201, which results in the energization of switching relay 2Ia and connection of the transformers 22a and 22a to the wattmeter I2. Voltages are thus applied to the wattmeter and its associated relay II or II is energized due to deflection of the indicator pointer into engagement with contact 29 or II and resulting connection of battery to relay 3. or ll associated with wattmeter I2 to permit the operation of its associated motor I! and the setting of its associated translating unit H to corres'pond'with the reading of the meter. Brush 302 has advanced to the second of the'contacts 304 so that battery is stillconnected to the winding of switching relay I80 which remains energized. No change in *circuit conditions occurs at the contact bank 5M, the brush "2 advancing to another contact which has no connection to any part of the circuit. Brush "2 has advanced to engagement with contact 604 0! contact bank SUI whereby battery is applied from I ll through conductor III, brush "2. contact I,

conductor II! to fixed contact I of switching relay 81. The potential applied to fixed contact Hi from sequence switch brush "2 replaces the TI potential applied through key' I I6 which may then be opened without affecting the operation of the transmitting system. I

Meanwhile, assuming that the indicator pointer 26 of voltmeter I l stands steadily deflected, and conductive pointer 26' engages neither of the contacts 29 and 30, the conductive path between switching relay and its energizing battery will be interrupted at conductive pointer 29, whereby relay 81 will be deenergized and contact arm H5 will be engaging contact H4 to apply an operating potential from sequence switch brush 502 to the winding of start magnet 15 which withdraws stop arm 14 from engagement, with transmitting distributing brush arm 13 and permits the lat ter to rotate. The brushes traverse first start segment 16 from which a start impulse is transmitted to the receiving printer. As the brushes leave the segment l6 the contact pair 89 opens and battery is disconnected from conductor 88, conductor 86, contact arm 84 of switching relay 3! and thus from indicator pointer 26 of voltmeter H. Since switching relays 38 and 39 can receive operating current only through indicator pointer 26 and one of its associated'contacts 29 or 30, it is impossible for either of the switching relays 38 and 38 to become energized so that if there is a subsequent change in the voltage condition which is now being interpreted by the voltmeter H and its associated translating unit 41 the positions of the commutators of the translating unit cannot be changed.

, As the transmitting distributor brushes traverse the four segments 85, impulses are impressed upon the telegraph line 11 in accordancewith the position of the commutator 52 with respect to its brushes 58 and in this way a code combination representing the tens digit of the reading of voltmeter II is transmitted over the line H to the receiving printer. After the code combination has been transmitted and the extra segment of the group has been traversed, the brushes traverse the stop and start segments to condition the printer to receive the next digit. The brushes then traverse the segments 83 which impress upon the line H impulses in accordance with the position of the units commutator 53 with respect to its brushes 51 and thus the units digit of the reading of voltmeter II is transmitted. As the brushes 12 leave the last of the segments 83, con-- tact pair 89 and the contact pair I03 are closed in a manner previously described to apply a voltage to the winding of switching relay 81 and to energize relay ll. Transmitting distributor brushes I2 continue to rotate and segment 98 is traversed, from which an impulse received from battery through the contact arm 94 engaging fixed contact 92 of switching relay 18 is impressed upon the line. This impulse in combination with the neutral condition of the segments preceding and following segment 96 constitutes a spacing signal under the control of which the receiving printer performs a spacing operation. As the impulse from segment 96 is being transmitted, contact pair I03 opens, and switching rea lay l0-l which had been energized to permit stepping magnet Ill to operate is deenergized. The operation of the stepping magnet Ill advances the brushes of the sequence switch to the next contact of each contact bank. While this is occurring, the brushes of the transmitting distributor continue to the end of their cycle of operation and transmit the finalstop signal of that cycle to the receiving printer.\

During the transmission of the reading of volt-* the wattmeter l2.

meter ll described in the preceding paragraph, the wattmeter I2 is conditioned to be read. This occurs by virtue of the ifact that the switching relay 2la is energized from the first of the contacts 201 of sequence switch bank 20l and deflection of the indicator pointer 26 of the wattmeter 12 under the influence ofimpressed voltage and current conditions causes the translating unit 4| associated therewith to be conditioned to transmit the reading of the wattmeter l2. As stated in the preceding paragraph, the sequence switch brushes were advanced upon the completion of the transmission of the second digit of the reading of-voltmeter H. Brush 202 advanced to the second of the contacts 201 and the switching relay 2la was thereby held energized; brush .302 advanced from the second 01' the contacts 306 to the first of the contacts 308, thereby disconnecting switching relay Ilia from battery and connecting switching relay l8b thereto. The effect of this is to connect the transformer lib to the voltmeter ll so that the reading of the voltage of the next circuit can be transmitted. There-is no change in circuit conditions as a result of the advance of brush 002,'but sequence switch brush 502 advances into engagement with contact 504 of contact bank 50! as a result of which battery is applied through conductor 506 to the winding of switching relay 31, thus causing the relay to be energized and the contact arms 19, 84, and 36 to move from the left-hand to the right-hand positions. In their new positions contact arms 19 connect the brushes of the translating unit M associated with the wattmeter i2 to the segments of the transmitting distributor. The contact arm 84 transfers control of the switching relay 8? from the indicator pointer of voltmeter H to that of wattmeter i2, and contact arm 38 transfers a direct battery connection from the indicator pointer of wattmeter A2 to that of the voltmeter l I.

With a 'circuit condition as described in the preceding'paragraph, the switching relay M is deenergized and battery is applied to the start magnet l providing indicator pointer of wattmeter H! has reached a steady deflection and engages neither of its associated contacts 20 or 30. When this condition exists, the start magnet "i5 is actuated to release transmitting distributor brushes, and the brushes traverse the segments "and transmit to the line H the proper start and stop impulses and the impulses supplied by the brushes ofthe translating unit associated with the wattmeter i2 so that the receiving printer may print the reading of that instrument. Upon the completion of the transmission of the reading, a spacing signal is transmitted as previously described, the sequence switch brushes are stepped to their next positions, and the brushes of the transmitting distributor complete a cycle of op-' eration. The advance of the sequence switch brushes brings brush 202 into engagement with the first of the contacts 208 whereby battery is disconnected from switching relay Ma and "is connected to switching relay 2lb so that the transformers 22b and 23b may be connected to Brush 302 advances to the second of the contacts 306 and holds batteryapplied to the winding of switching relay l6b. Brush 502 advances from contact 504 to a free or dead contact, thus removing battery from the conductor 506. and permitting switching re- 19 and the contact arms 84 and 36 return to their left-hand position to permit the reading lay 31 to be deenergized. All of the contact arms llli oi. the voltmeter ii which is then under influence of the circuit associated with the transformer ill) to be transmitted to the line W.

In the manner described in the foregoing paragraphs, the transmission of readings of the meters proceeds, the meters being connected alternately to power circuits to be conditioned and to the transmitting distributor for the transmission of a reading so that while the translator M of one meter is being conditioned, the reading of the other is being transmitted. With each cycle of operation of the transmitting distributor, impulses, representing two digits and a spacing signal are transmitted. Eventually the sequence switch brush 202 comes into engagement with the last contact of the bank Mi which is the second of the contacts identified by the reference numeral m. At the same time the brush 3% comes into engagement with the contact Mill of bank till, which is the last contact of that bank and which is connected by conductor (iiil to the previously described contacts 55M. When this occurs, the wattmeter it, which would be conditioned for reading during the preceding cycle of operation of the transmitting distributor, has its translating unit ti connected to the segments of the transmitting distributor by reason of the energization of the switching relay 3! from the last contact of contact banlrhdll which is then engageci by brush our. During this transmission of the wattmeter reading, the switching relay its is energized as a result of its connection to contact Mill to which battery is connected from the brush till. and the translating unit associated with the voltmeter ii is conditioned for transmission of the reading of the meter. As the next cycle of operation of the transmitting distributor is completed, the brushes of the sequence switch advance to the positions shown in Fig. 1, which has been described as the initial or starting condition. Brush 202 connects battery to conductor 206 from which switching relay 18 is energized to disconnect the translating unit brushes from thesegments of the transmitting distributor and to connect to the proper segments of the transmitting distributor the potentials required to provide carriage return and line feed signals. Switching relay Ilia remains energized for the reason that sequence switch brush 302 again engages the first of the contacts 30!. Sequence switch brush 502 engages an idle contact so that 7,

also engages a dead contact and the potential for operating the start magnet 15 which would be applied thereto through the conductor I I1 and contacts I and H5 is rembved so that the start magnet is unable to release the brushes I2 for the transmission of the carriage return and line feed signals. In order for the apparatus to be started again, it is necessary'to close the key H6 manually or by remote control to apply a potential to the start magnet I5 release the transmitting distributor brushes for a cycle 01' operation during which, as previously described, the sequence switch brushes are advance and a local potential is applied to the start from the sequence switch brush B02. The functions of the switching relays 31 and 01 are of sumcient' importance to merit particube transmitted.

to connecting one or the other of the two trans- ,latin'g units to the transmitting distributor also connects-the indicator pointer of that instrument from which areading is about to be transmitted to battery through the winding oi. switching re assay-ii.

lay av, which receives battery through the contact pair til. Thus, if a meter has not reached a stable condition as the transmitting distributor brushes approach their starting point, one of the relays 3&3 or 39 will be in a state of energization to permit the motor 35 to move the contact arms it audit, and the current which energizes the relay 38 or 39 will also traverse and energize the winding of relay 8? to cause the contact pair lit-i id to open. When these contacts are opened, the start magnet 15 cannot be energized from the sequence switch brush 602 and, therefore, the transmitting distributor is not permitted to start until a stable condition of the meter, the reading of which is to be transmitted, is reached. In addition to controlling the circuit arrangement of the switching relay 81, with respect to the conductive pointers of the meters II and 92, the switching relay 3'! also shifts from one to another of the pointers direct battery connection through the contact arm 38 to provide the potential for the operation of the relay 38 or II associated with a meter which is to be conditioned to have its reading transmitted.

The provision of thecontact pair 89 in the circuit of the switching relay 0'! provides for an unchanging condition of a translating unit during the transmission of a reading therefrom. The timing of these contacts is such that they are open during the time that those segments of the transmitting distributor which carry meter reading signal impulses are traversed by the brushes. During this interval, the pointer 01 the meter, the reading of which is being transmitted, cannot receive battery from the contacts 89; therefore neither of its associated relays 38 or 39 can be energized and the motor 35 oi. its translating unit cannot be started.

Only the starting of the system can be accomplished by closure of the key H6 or by remote control. Its operation cannot be interrupted by any recognized or conventional means during the transmission of the readings of conditions of a series of power circuits. A potential for operating thestart magnet 15 is available at the contact bank GM of the sequence switch in all positions 01' the brush except the position shown in Fig. 1. When the apparatus has once been started, it will continue to operate until the sequence switch brushes have traversed all of the contacts and have returned to the initial position, and in this cycle of operation of the sequence switch, the readings of circuit conditions of all power circuits connectible to the meters under the control of the several sequence switch contacts will AS previously described 'the transmitting diatributor segment 96 in combination with the adjacent numbered segments provides a spacing signal combination whereby the receiving printer is caused to perform a spacing operation after the reception of each two-digit meter reading. In this way voltmeter and wattmeter readings are printed alternately in a line across a. page with a space between each two readings and a line is completed when voltmeter and wattmeter readings for all of the-power circuits to be metered under thecontrol of the sequence switch have been recorded. In the next cycle of operation, the transmitting distributor impresses upon the telegraph line impulses which, cause the receiving printer to perform line feed and carriage return functions. The carriage of the printing apparatus is thus presented at the beginning of a line, and the paper on which the readings are printed is advanced to present a blank line to the printing point. If the transmitting apparatus is then started in order that the several power circuits may again be metered, the voltmeter reading from the circuit associated with transformer-Ha. will be printed directly under the preceding reading for that circuit, the receiving printer will perform a spacing operation,

and the wattmeter reading for the power circuit resent voltmeter readings for the circuit associated with the transformer Ha, the readings in the second column would represent wattmeter readings for the same power circuit, and the readings in the third and fourth columns would.

represent voltmeter and wattmeter readings respectively for the power circuit associated with the transformers I'Ib, 22b, and 231).

It will be observed that the system herein described provides for a minimum of idle telegraph line time for the reason that two meters are provided, the readings of which are transmitted alternately so that the time required for conditioning one meter to a steady deflection does not represent a waste of line time, as a reading is being transmitted from the other meter. The; transmission of impulses representing the true reading of a meter is assured by an automatic adjustment of the brushes associated with the tens digit commutator in relation to certain positions of the units digit commutator. The brushes are carried, forward or backward with respect to the commutator as the units digit commutator'passes between a surface zone representing 9 and one representing zero so that errors due to failures of carry-over of the tens digit coding-apparatus cannot occur. "The possibility of errors in recording of readings is eliminated by preventing the transmission of readings until a meter has reached a steady deflection. Thepossibility of errors due to changing circuit conditions in the power circuits during the transmission of a, reading is eliminated by disabling the motor which 'actuates a translating unit at the time: that the transmission of a reading from that translating unit begins and continuing such disablement until the transmission of the readings has-been completed. The transmission of meter readings for all circuits associated with the system is assured by pro-- viding a local source of potential for operating the start magnet of the transmitting distributor which is brought into effective connection with the start magnet when the system is started either locally or by remote control and which cannot be disconnected from the start magnet by local or remote control during the transmission of a series of readings, but can only be disconnected by the return of the sequence switch brushes'to their normal or initial .positions. Y

Although a specific embodiment of the invention has been described in the foregoing specification, it is to be understood that the invention is capable of modification and substitution as to the elements entering into the system, and as to the combination and arrangement of the elements, within the scope of the appended claims.

What is claimed is:

1. In a coding device, a conductive member affording various combinations-of elemental areas such that a code generated by the random selection of elemental areas from any two adjacent combinations of elemental areas is exactly identical with one of said combinations.

2. In a'coding device, a plurality of commutators geared together for related rotation, said commutators having continuous conductive areas arranged in accordance with a code, collector brushes bearing against the commutators, and

means operated under the control of a brush associated with certain conductive areas of one of said commutators when said commutator reaches a position where the code engaged by the brushes associated with the other commutator should be changed for shifting the brushes with respect to the other commutator to change said code.

3. In a coding device, a pair of commutators geared together for predetermined relative rotation, saidcommutators consisting of electrically continuous conductive areas arranged in accord-v ance with a code; collector brushes bearing against said commutators, the brushes bearing against .one commutator being fixed and the brushes bearing against the other commutator being movable circumferentially thereof, and an electromagnet energizable under the control of one of the fixed brushes when-the commutator engaged by said fixed brush reaches a. position where the codepresented to the movable brushes by the other commutator should be changed to the next code for shifting the to assure the changing tosaid code.

"4. In a coding device, a plurality of commutators geared together for related rotation, each.

commutator having electrically continuous conductive areas on the surface thereof, collector brushes bearing against thesurface of one of the commutators and presentable in either of two' positions peripherally thereof, and means for shifting said brushes from one to the other of said positions when the other of said commutators reaches a position where the code presented to said brushes should be changed to thenext code for changing to said next code.

5. In acoding device, a plurality of commutators geared together for related rotation, said commutators having physically and electrically continuous conductive areas on the surface thereof, collector brushes bearing against the surface -of one of said commutators and presentable in either of two positions peripherally thereof for shifting from one to the other-of two' codes on said one commutator, and means for shifting said brushes controlled by the other commutator when said other commutator reaches a position where the code presented to the shiftable brushes should be changed to the next code.

. EDWARDS. mason.

movable brushes 

